Post-traumatic stress disorder (PTSD) is one of the most disabling psychopathological conditions affecting the veteran population. Approximately 15.2% of the men and 8.5% of the women stationed in Vietnam were found to be suffering from PTSD 15 or more years after their service. In the Atlanta metropolitan area, some 9000 Vietnam veterans suffer from complete or partial PTSD. The psychological, social, occupational and economic consequences of the disorder for patients and their families are devastating. No therapeutic approach has proven to be consistently effective in the management of combat- related PTSD. The present proposal intends to exploit the potential therapeutic effectiveness of recent advances in computer and display technology referred to as Virtual Reality. Virtual reality exposure (VRE) takes place in an immersive, computer-driven environment. Patients would be exposed to virtual Huey helicopters flying them over the jungles of Vietnam. They will be encouraged to relive their traumatic memories, much as in standard exposure therapy, but immersed in Vietnam stimuli. Ultimate control is possible in the virtual environment, changing levels of intensity of exposure instantly. The proposed project aims to develop virtual reality exposure therapy for Vietnam veterans with PTSD, revise and perfect the treatment, construct a treatment manual, and gather preliminary evidence of its efficacy in a small group design. A series of five case studies will be run to develop and revise the treatment. Following this, Vietnam veterans (n=40) with current DSM-IV PTSD diagnoses will be randomly assigned to VRE or a wait-list control. Treatment will be delivered in nine 60-minute individual sessions conducted over 5 weeks. Assessments will be conducted at pre-treatment, post-treatment and follow-ups of 6 and 12 months post-treatment. Assessments will be conducted by an independent assessor who will be kept blind to the treatment condition. Objective clinician-rated and self report measures of PTSD will be incorporated.